In a conventional CVD system, a film is formed on a wafer utilizing a chemical reaction with a reaction gas. Accordingly, by-product particles form on the gas releasing surface of the gas dispersing device, and further these particles separate from the gas releasing surface and then stick to the wafer, thereby causing contamination of the wafer. Therefore, in the CVD system, it is necessary to clean the gas releasing surface of the gas dispersing device on a specified cycle.
In a plasma CVD system, even if by-product particles stick to the gas releasing surface of a gas dispersing device, the inside of a chamber can be depressurized and thereby the particles stuck on the gas releasing surface can be simply removed by introducing an etching gas into the chamber after the formation of a film. This technique, which is called an in-situ cleaning, is conventional practice.
In an atmospheric pressure CVD system, when a reaction gas such as a mixed gas of SiH.sub.4 --O.sub.2 or TEOS--O.sub.3 is released from a gas releasing device, the reaction products stick to the gas releasing surface as powder-like particles. However, in this CVD system, since the inside of the chamber cannot be depressurized, it is impossible to perform the in-situ cleaning, and it thereby differs from the above plasma CVD system. Accordingly, the particles on the gas releasing surface must be physically removed by a cleaner or chemically removed by chemicals such as hydrofluoric acid (HF) after stopping this CVD system.
As a result, in the atmospheric pressure CVD system, the cleaning takes a lot of time or labor thereby reducing the uptime/downtime ratio thereof. Also, in this system, the deposited powder can accummulate to the point where it is difficult to remove.
Taking the above conventional problems into consideration, the present invention has been made, and an object is to provide a semiconductor fabrication apparatus and method using the same, wherein the dust generated in a chamber can be easily removed without reducing the uptime/downtime ratio of the equipment.